Stacking device



Aug. 28, 1962 E. RICHERT ETAL 3,

STACKING DEVICE Filed Nov. 24, 1958 INVENTORS E.RICHERTH.FLIEGNEH BY m United States Patent lice 3,051,332 STACKIN G DEVICE Eberhard Richert, Berlin-Steglitz, and Horst Fliegner, Berlin-Lankwitz, Germany, assignors to International Standard Electric Corporation, New York, N.Y., a corporation of Delaware Filed Nov. 24, 1958, Ser. No. 775,769

Claims priority, application Germany Dec. 19, 1957 4 Claims. (Cl. 214-7) This invention relates to improvement in materials handling machinery, and more particularly to an arrangement for stacking fiat articles.

The invention concerns an arrangement by which flat articles, especially post letters and cards, arriving in succession from a conveyor, can be arranged in layers to form a stack or pile. As the invention is to be used preferably for stacking of post letters, only these will hereafter be mentioned, but it will be understood that the arrangement provided by the invention is also suitable for other articles or legendized papers, as, for example, flat packages or similar objects.

In these arrangements the letters are led to a stacking equipment by two conveying belts between which they are contained. One arrangement of this kind utilizes a second belt conveyor arranged to draw each arriving letter from the prior conveyor against a stop thereby defleeting the letter so as to lift it off the prior conveyor and thereby to enable a subsequent letter to be shifted into between the preceding letter and the second conveyor. In this way the letters are brought to build up a stack vertically to the second or stacking conveyor. This action is achieved with the aid of a supporting plate which is parallel to the second conveyor and movable at right angles :to it, and may form part of a carriage for the stack.

This arrangement has drawbacks that endanger the operation. In the first place it is disadvantageous that the letters when arriving at the second conveyor are defiected by this at an angle of some 30 and thus bent to an undesirable degree in many cases. Also there is the danger that the stacking will not be performed correctly because the letters being inserted into the stack can be injured during this action. For example, it is possible that the leading edge of a letter will abut against the trailing edge of the preceding letter. The succeeding letter can thus be either bent up or bent inward, or can deform the preceding letter. Also the preceding letter may be so turned that its elasticity acts either to eject the succeeding letter or to prevent subsequent letters from reaching the stacking conveyor.

In order to avoid these shortcomings, the arrangement according to the invention has two consecutive belt conveyors of which the first delivers the letters to the second or stacking conveyor. This acts to deflect the letters toward a guide roller which cooperates with one of the belt conveyors and then to shift the letters toward a stop for them, the belt length by which this shifting is done running parallel to a movable supporting plate that may form part of a stacking carriage forced toward the stacking conveyor. These two conveyors are so positioned as to form on the stacking side an obtuse angle of less than 180.

The belt length of the stacking conveyor which runs between the said guide roller and the stop for the letters should preferably be shorter than the length of the shortest letter to be stacked. Appropriately this guide roller is so positioned that the belt length between it and the stop for the letters is parallel to the belt of the first conveyor. By this roller the belt ply on the stacking side is divided into a length that deflects each letter toward 3,051,332 Patented Aug. 28, 1962 the stack, and a length by which this letter is then inserted into the stack.

The safety of operation can further be increased through providing that the speed of the second conveyor shall be higher than that of the first conveyor. For this purpose the two conveyors may be driven with the aid of rollers having different diameters but rotatably mounted on a common axle; the smaller roller serving to drive the first conveyor, called a feeder conveyor, and the larger roller acting to drive the second or stacking conveyor.

A third provision to increase the safety of operation is that the said supporting plate, or the carriage fitted with it, is movable in a direction not normal to the stack but diagonally thereof and in opposition to the direction of conveyance. In this way the kinetic energy of each arriving letter is utilized for the shifting of this plate, or of the carriage containing it. The growth of the stack will thus be favored.

Owing to these provisions the leading edge of a letter running toward the stack will not be deflected until its leading edge has passed by the trailing edge of a preceding letter added to the stack. Accordingly any incoming letter will no longer be able to abut against the trailing edge of the preceding letter.

The above-mentioned and other features and objects' of the invention and the manner of attaining them will become more apparent and the invention itself will be best understood by reference to the following description of an embodiment of the invention taken in conjunction with the accompanying drawing in which:

FIG. 1 is a diagrammatic plan view of a stacking arrangement of the customary design; and

FIG. 2 is a diagrammatic plan view of a stacking arrangement containing the features of the invention.

Referring now to FIG. 1, there is shown diagrammatically a driving motor 1 coupled to pulley 1a. A conveyor belt 1b runs over pulley 1a and a first portion of pulley 8. A second conveyor belt 5 runs over pulley 5a and a second portion of pulley 8. Thus, the motor 1 drives both belts. A third belt, 2b running over pulley 2 is parallel to the belt 1b and in close contact therewith, whereby the contacting surfaces of said belts move in the same direction. Thereby an article clamped between the contacting surfaces of the belts will be moved by them in the direction of the arrow. As the articles 3 are ejected from between belts 1b and 2b, they will be introduced into the stack 4 of previously deposited articles. The stack 4 is created by the stops 6 and 7 at right angles to each other. Stop 6 limits longitudinal motion imparted to the articles by conveyor 5 and stop 7, laterally supports the stacked articles and urges the stack against conveyor 5. Stop 7 may form part of a movable carriage. Means for restraining stop 7 or controlling the movement of a carriage containing stop 7 to accommodate a growing stack is well known in the art. The angle which the conveyor belts 1b and '5 form on the stacking side is greater than It will be seen that the articles, especially long letters, will be considerably bent by the roller 8 common to conveyor belts 1b and 5. Such bending is undesirable in many cases since the articles to be stacked can thereby be injured.

According to the invention shown in FIG. 2, the conveyors 1b, 5, may be driven by motive means similar to that shown in FIG. 1 and are so positioned that the angle they form on the stacking side is obtuse by less than 180. The arrangement is such that an article arriving between conveyor 1b and the conveying belt 2b which extends over pulley 2a will be slightly deflected by conveyor 5 so as to abut against the outer face of the last article already stacked and then to be drawn by conveyor belt 5 onto stack 4 and against stop 6. A guide roller or idler 9 is arranged to bulge the belt of conveyor toward stack 4 and to such extent that the belt length between the pulleys 9 and shall be parallel to the belt lb or nearly so. It can be seen that, in distinction from the prior arrangement of FIG. 1, a letter 3 shown in dashed line, will be bent but slightly, so the demand on it will be much less. Here too a stop 7, that may be part of a movable carriage, is pressed against the stack 4. This plate or the carriage is, however, movable not normal to the stack but diagonally thereof and thus also diagonally to the direction in which the articles to be stacked are moving.

In order that the two conveyors may be movable at speeds mutually different, two pulleys 8a, 8b, having different diameters, are rotatably mounted on the same axle. Pulley 8a, of the smaller diameter drives the conveyor 1b, and pulley 8b of the larger diameter drives the conveyor 5.

The letters are moved toward the pulleys 8a, 8b by a pair of rollers 2 a, 2c. These are so positioned that the geometrical line by which their axes can be connected with each other is somewhat inclined with respect to conveyor belt 112, so that each article 3, passing through between the rollers 20, 2b shall be pressed against conveyor belt 1b. The rollers 2a, 2c are spaced at such a distance from the pulleys 8a, 8b that any article shall not arrive at the pulleys 8a, 8b until the trailing edge of a preceding letter has been lifted off conveyor 1b.

While I have described above the principles of my invention in connection with specific apparatus, it is to be clearly understood that this description is made only by way of example and not as a limitation to the scope of my invention as set forth in the objects thereof and in the accompanying claims. 2

What is claimed is:

1. An arrangement for stacking flat articles in an edgewise conveying system comprising an edgewise conveying means for conveying flat articles, a stacking belt having a sloped section which intercepts articles delivered from said edgewise conveying system at an obtuse angle which is less than to impart a sideways as well as a forward motion to said articles, said stacking belt having a further section following said sloped section which is shorter than the shortest article to be stacked and substantially parallel to said edgewise conveying means, a stack supporting plate parallel to and urged towards said further section of said stacking belt to allow an arriving article to move therebetween, a stop member disposed at an acute angle to said supporting plate to stop an article between said stacking belt and said sup-porting plate so that a stack of such articles may be formed.

2. An arrangement as claimed in claim 1, further comprising means for driving said edgewise conveying means and stacking belt.

3. An arrangement as claimed in claim 2, further comprising a stepped pulley common to said edgewise conveying means and said stacking belt, said stacking belt cooperating with the larger diameter surface of said pulley and said edgewise conveying means cooperating with the smaller diameter surface of said pulley, whereby said stacking belt moves at a speed greater than that of said edgewise conveying means.

4. An arrangement as claimed in claim 1, wherein said supporting plate comprises a carriage movable diagonally with respect to the direction of movement of said stacking belt.

References Cited in the file of this patent UNITED STATES PATENTS 2,592,642 Bardet Apr. 15, 1952 2,772,880 Garrett Dec. 4, 1956 FOREIGN PATENTS 196,789 Austria Mar. 25, 1958 504,461 Belgium July 31, 1951 

